Gearbox For Vehicle Seat Adjustment Mechanism

ABSTRACT

A gearbox for a vehicle seat adjustment mechanism in accordance with the principles of the present disclosure includes first and second portions. The first portion includes a first body defining a first longitudinal recess and a first peripheral recess in fluid communication with the first longitudinal recess. The first body includes a concave first curved surface. The second portion includes a second body defining a second longitudinal recess and a second peripheral recess in fluid communication with the second longitudinal recess. The second body includes a convex second curved surface. The second curved surface has an equal and opposite curvature compared to the first curved surface. In an assembled configuration, the first and second curved surfaces are in contact, the first longitudinal and second longitudinal recesses cooperate to define a longitudinal passage, and the first and second peripheral recesses communicate to define a peripheral receptacle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.63/019,054, filed on May 1, 2020. The entire disclosure of the aboveapplication is incorporated herein by reference.

FIELD

The present disclosure relates to generally to gear drives caseassemblies for vehicle seat adjusters and more particularly to abi-directionally self-centered case for an orthogonal gear drive (e.g.,of enveloping or helical type) used in adjusting longitudinal positionof a vehicle seat.

BACKGROUND

This section provides background information related to the presentdisclosure and is not necessarily prior art.

Vehicles such as automobiles are commonly equipped with seat adjustermechanisms, that can primarily adjust the height, tilt and/orlongitudinal position of the driver or/and passenger seat, toaccommodate occupants of different size and height as well as to providea comfortable seating position to suit the occupant's preference. Suchseat adjusters may be manually or powered operated.

Power operated seat adjusters are driven by electric motors, their sizebeing directly linked to the torque they must provide to produce therequired motion. Thus, if a reasonably high reduction gear ratio can beachieved in very limited space, smaller and faster electric motors canbe used to providing the same level of mechanical power needed for therequired function. Electric motors with increased speed and capable ofdelivering a certain level of torque, used in certain applicationsrequire a limited reduction gear ratio but in a very compact dimensionalspace.

Electric motor-driven adjusting devices offer various advantages overmanual adjustment devices. User comfort may be enhanced. Electricmotor-driven adjusting devices also provide an electric interface whichlends itself to automation, e.g. under the control of a controller of avehicle which may automatically control the motor to bring the seat to adesired state. In spite of the benefits offered by electric motor-drivenadjusting devices, packaging is an issue in many seats.

Typically, a power operated seat length adjuster is actuated by anoccupant-controlled switch and includes a bi-directional electric motor,mounted centrally or intermediately between the vehicle seat pair oftrack assemblies, that rotates two flex drive shafts extending outwardlyfrom the motor to two gearbox blocks fixedly mounted inside of eachupper or inner track assemblies. Each gearbox block includes a worm-wormgear or a worm-helical gear drive assembly, having the drive memberactuated through the flex drive shaft and the driven member integralwith an internal threaded spindle nut.

Each spindle drive assembly includes the already mentioned rotatablespindle nut that threadingly receives a lead screw extendinglongitudinally along and fixed to the lower or outer track assembly.Through these two drives, the electric motor rotational movement isorthogonally offset to move fore/and aft linearly the upper tracksrelative to the lower tracks, along spindle screws axes. The vehicleseat is attached to on a frame supported by the seat pair of mobileupper tracks disposed parallel to one another, while the pair of lowertracks is fastened to the vehicle chassis. Typically, two drive shafts,gear boxes, lead screws, and drive nuts are employed in a power lengthadjuster drive, one set for each seat track assembly, driven by only onebi-directional electric motor.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

A gearbox for a vehicle seat adjustment mechanism in accordance with theprinciples of the present disclosure is provided. The gearbox includes afirst portion and a second portion. The first portion includes a firstbody. The first body defines a first longitudinal recess and a firstperipheral recess in fluid communication with the first longitudinalrecess. The first body includes a first curved surface. The first curvedsurface is concave. The second portion includes a second body. Thesecond body defines a second longitudinal recess and a second peripheralrecess in fluid communication with the second longitudinal recess. Thesecond body includes a second curved surface. The second curved surfaceis convex. The second curved surface has an equal and opposite curvaturecompared to the first curved surface. In an assembled configuration, thefirst curved surface is in contact with the second curved surface. Inthe assembled configuration, the first longitudinal recess communicateswith the second longitudinal recess to define a longitudinal passage. Inthe assembled configuration, the first peripheral recess communicateswith the second peripheral recess to define a peripheral receptacle.

In one implementation, the first curved surface and the second curvedsurface both define (i) a portion of an ellipsoidal surface, (ii) aportion of a conical surface, or (iii) a portion of a spherical surface.

In one implementation, the first curved surface and the second curvedsurface both define a portion of an ellipsoidal surface. The ellipsoidalsurface has a first radius in a range of 190 mm to 200 mm and a secondradius in a range of 240 to 250 mm.

In one implementation, the first curved surface and the second curvedsurface both define a portion of a conical surface. The conical surfacedefines an average opening angle in a range of 165° to 172°.

In one implementation, the first curved surface and the second curvedsurface both define a portion of a spherical surface. The sphericalsurface has a radius in a range of 190 mm to 200 mm.

In one implementation, one of the first portion and the second portionincludes a frusto-conical projection extending from a respective one ofthe first curved surface and the second curved surface. The other of thefirst portion and the second portion includes a frusto-conicalreceptacle defined by a respective one of the first curved surface andthe second curved surface. In the assembled configuration, thefrusto-conical receptacle receives the frusto-conical projection.

In one implementation, the one of the first portion and the secondportion further includes an annular projection extending from therespective one of the first curved surface and the second curvedsurface. The annular projection is disposed around a base of thefrusto-conical projection. The annular projection is coaxial with thefrusto-conical projection. The other of the first portion and the secondportion further includes an annular depression defined by a respectiveone of the first curved surface and the second curved surface. Theannular depression is coaxial with the frusto-conical receptacle. In theassembled configuration, the annular depression receives the annularprojection.

In one implementation, the frusto-conical projection includes a firstfrusto-conical projection and a second frusto-conical projection. Thefrusto-conical receptacle includes a first frusto-conical receptacle anda second frusto-conical receptacle. The annular projection includes afirst annular projection and a second annular projection. The annulardepression includes a first annular depression and a second annulardepression.

In one implementation, the gearbox further includes an elastic layer.The elastic layer is disposed on at least one of the first curvedsurface or the second curved surface.

In one implementation, one of the first portion and the second portionincludes an integral rivet. The integral rivet extends from a respectiveone of the first curved surface and the second curved surface. The otherone of the first portion and the second portion includes an aperturedefined in a respective one of the first curved surface and the secondcurved surface, the aperture is configured to receive a portion of theintegral rivet.

In one implementation, the gearbox further includes a plurality offasteners. The plurality of fasteners is configured to couple the firstportion and the second portion to each other.

In one implementation, the gearbox is configured to house at least aportion of a cross-axis gear system and a spindle screw. The cross-axisgear system includes a first gear in operative communication with asecond gear. The second gear is in operative communication with thespindle screw.

In one implementation, the gearbox is a universal gearbox. The gearsystem is configured to operate at any one of: (i) a comfort speed has alinear adjusting speed ranging from 17 mm/s to 22 mm/s, (ii) a highspeed has a linear adjusting speed ranging from 50 mm/s to 55 mm/s, or(iii) a ultra-high speed has a linear adjusting speed ranging from 80mm/s to 85 mm/s.

In one implementation, the first gear is a cylindrical worm gear and thesecond gear is one of a helical gear or a single enveloping worm gear.

A vehicle seat adjustment assembly in accordance with the principles ofthe present disclosure is provided. The vehicle seat adjustment assemblyincludes a gearbox, a gear system, and a spindle screw. The gearboxassembly includes a first portion and a second portion. The firstportion includes a first body. The first body defines a firstlongitudinal recess and a first peripheral recess in fluid communicationwith the first longitudinal recess. The first body includes a firstcurved surface. The first curved surface is concave. The second portionincludes a second body. The second body defines a second longitudinalrecess and a second peripheral recess. The second body includes a secondcurved surface. The second longitudinal recess cooperates with the firstlongitudinal recess to define a longitudinal passage. The secondperipheral recess cooperates with the first peripheral recess to definea peripheral receptacle. The second curved surface is convex, has anequal and opposite curvature compared to the first curved surface, andis in contact with the first curved surface. The gear system includes afirst gear and a second gear. The first gear is disposed at leastpartially within the peripheral receptacle. The first gear includes afirst external thread. The first gear is configured to rotate about afirst axis. The second gear is disposed at least partially within thelongitudinal passage. The second gear includes external teeth and aninternal thread. The second gear defines a gear passage. The externalteeth are in operative communication with the first external thread. Thesecond gear is configured to rotate about a second axis perpendicular tothe first axis. The spindle screw extends through the gear passage. Thespindle screw includes a second external thread. The second externalthread is in operative communication with the internal thread.

In one implementation, the first curved surface and the second curvedsurface both define (i) a portion of an ellipsoidal surface, (ii) aportion of a conical surface, or (iii) a portion of a spherical surface.

In one implementation, the second gear is one of (i) a helical gear or(ii) a single enveloping worm gear.

In one implementation, the second external thread is a trapezoidalthread, and the spindle screw has a 3 mm lead, a 1.5 mm pitch, and oneof a (i) 8 mm nominal diameter and (ii) a 9 mm nominal diameter.

In one implementation, the gear system is configured to operate at oneof: (i) a comfort speed has a linear adjusting speed ranging from 17mm/s to 22 mm/s, (ii) a high speed has a linear adjusting speed rangingfrom 50 mm/s to 55 mm/s, or (iii) a ultra-high speed has a linearadjusting speed ranging from 80 mm/s to 85 mm/s.

In one implementation, one of the first portion and the second portionincludes a frusto-conical projection and an annular projection extendingfrom a respective one of the first curved surface and the second curvedsurface. The annular projection is disposed around a base of thefrusto-conical projection and coaxial with the frusto-conicalprojection. The other of the first portion and the second portionincludes a frusto-conical receptacle and an annular depression definedby a respective one of the first curved surface and the second curvedsurface. The annular depression coaxial with the frusto-conicalreceptacle. The frusto-conical receptacle is configured to receive thefrusto-conical projection and the annular depression is configured toreceive the annular projection.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a partial perspective view of a vehicle seat assembly having apair of seat track assemblies, each including a power seat lengthadjustment assembly in accordance with the principles of the presentdisclosure;

FIG. 2 is a perspective view of the power seat length adjustmentassembly of FIG. 1;

FIG. 3 is an exploded perspective view of an adjustment subassembly ofthe power seat length adjuster assembly of FIG. 2;

FIGS. 4A-4E relate to a close-type gearbox having ellipsoidal matingsurfaces in accordance with the principles of the present disclosure;FIG. 4A is a perspective view of the gearbox and a representativeellipsoid; FIG. 4B a perspective view of the gearbox; FIG. 4C is a firstside view of the gearbox; FIG. 4D is a second side view of the gearbox;and FIG. 4E is an exploded perspective view of the gearbox;

FIGS. 5A-5B relate to an open-type gearbox having ellipsoidal matingsurfaces in accordance with the principles of the present disclosure;FIG. 5A is a perspective view of the gearbox; and FIG. 5B is an explodedperspective view of the gearbox;

FIGS. 6A-6D relate to an open-type gearbox having conical matingsurfaces in accordance with the principles of the present disclosure;FIG. 6A is a perspective view of the gearbox and a representative cone;FIG. 6B is a first side view of the gearbox; FIG. 6C is a second sideview of the gearbox; and FIG. 6D is an exploded perspective view of thegearbox;

FIGS. 7A-7E relate to an open-type gearbox having spherical matingsurfaces in accordance with the principles of the present disclosure;FIG. 7A is a perspective view of the gearbox and a representativesphere; FIG. 7B is a perspective view of the gearbox; FIG. 7C is a firstside view of the gearbox; FIG. 7D is a second side view of the gearbox;and FIG. 7E is an exploded perspective view of the gearbox;

FIG. 8A-8B relate to preassembly join stop features; FIG. 8A is a detailperspective view of a depression of a preassembly join stop feature ofthe gearbox of FIG. 5B; and FIG. 8B is a detail perspective view of aprotrusion of the preassembly join stop feature of FIG. 5B;

FIG. 9 is an exploded perspective view of a gearbox including a singlejoin stop feature in accordance with the principles of the presentdisclosure;

FIG. 10 is an exploded perspective view of a gearbox that is free ofpreassembly join stop features in accordance with the principles of thepresent disclosure;

FIGS. 11A-11B relate to a gearbox including an elastic layer inaccordance with the principles of the present disclosure; FIG. 11A is anexploded perspective view of the gearbox; and FIG. 11B is a perspectiveview of the gearbox;

FIGS. 12A-12C relate to a gearbox assembly including the gearbox ofFIGS. 5A-5B assembled with screws in accordance with the principles ofthe present disclosure; FIG. 12A is a perspective view of the gearboxassembly; and FIG. 12B is a partial sectional view taken at line 12B-12Bof FIG. 12A; FIG. 12C is a sectional view taken at line 12C-12C of FIG.12A;

FIGS. 13A-13D relate to a gearbox assembly including the gearbox ofFIGS. 5A-5B assembled with discrete rivets in accordance with theprinciples of the present disclosure; FIG. 13A is an explodedperspective view of the gearbox assembly with the rivets in anundeformed state; FIG. 13B is a perspective view of the gearbox assemblywith the rivets in the undeformed state; FIG. 13C is a sectional view ofthe gearbox assembly taken at line 13C-13C of FIG. 13B, the rivets inthe undeformed state; and FIG. 13D is a sectional view of the gearboxassembly taken at line 13D-13D of FIG. 13B, the rivets in a deformedstate;

FIGS. 14A-14D relate to a gearbox assembly including a gearbox havingintegral rivets in accordance with the principles of the presentdisclosure; FIG. 14A is an exploded perspective view of the gearbox withthe rivets in an undeformed state; FIG. 14B is a perspective view of thegearbox with the rivets in the undeformed state; FIG. 14C is a sectionalview taken at line 14C-14C of FIG. 14B, the rivets in an undeformedstate; and FIG. 14D is a sectional view taken at line 14D-14D of FIG.14B, the rivets in a deformed state;

FIGS. 15A-15D relate to an enhanced-strength, enveloping-gear,comfort-speed power length adjustment assembly in accordance with theprinciples of the present disclosure; FIG. 15A is a partial perspectiveview of the adjustment assembly; FIG. 15B is a partial perspectivecutaway view of the adjustment assembly; FIG. 15C is a sectional view ofthe adjustment assembly taken at line 15C-15C of FIG. 15A; and FIG. 15Dis a sectional view of the adjustment assembly taken at line 15D-15D ofFIG. 15A;

FIGS. 16A-16E related to an enhanced-strength, helical-gear,comfort-speed power length adjustment assembly in accordance with theprinciples of the present disclosure; FIG. 16A is a partial explodedperspective view of the adjustment assembly; FIG. 16B is a partialperspective view of the adjustment assembly; FIG. 16C is a partialperspective cutaway view of the adjustment assembly; FIG. 16D is asectional view of the adjustment assembly taken at line 16D-16D of FIG.16B; and FIG. 16E is a sectional view of the adjustment assembly takenat line 16E-16E of FIG. 16B;

FIGS. 17A-17D relate to a normal-strength, enveloping-gear, high speedpower length adjustment assembly in accordance with the principles ofthe present disclosure; FIG. 17A is a partial perspective view of theadjustment assembly; FIG. 17B is a partial perspective cutaway view ofthe adjustment assembly; FIG. 17C is a sectional view of the adjustmentassembly taken at line 17C-17C of FIG. 17A; and FIG. 17D is a sectionalview of the adjustment assembly taken at line 17D-17D of FIG. 17A;

FIGS. 18A-18D relate to a normal-strength, helical-gear, high speedpower length adjustment assembly in accordance with the principles ofthe present disclosure; FIG. 18A is a partial perspective view of theadjustment assembly; FIG. 18B is a partial perspective cutaway view ofthe adjustment assembly; FIG. 18C is a sectional view taken at line18C-18C of FIG. 18A; and FIG. 18D is a sectional view taken at line18D-18D of FIG. 18A; and

FIGS. 19A-19D relate to a normal-strength, helical-gear, ultra-highspeed power length adjustment in accordance with to the principles ofthe present disclosure; FIG. 19A is a partial perspective view of theadjustment assembly; FIG. 19B is a partial perspective cutaway view ofthe adjustment assembly; FIG. 19C is a sectional view taken at line19C-19C of FIG. 19A; and FIG. 19D is a sectional view taken at line19D-19D of FIG. 19A.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific components, devices, and methods, to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to those skilled in the art that specific details need not beemployed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly connected to,” or “directly coupled to” another elementor layer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Although the terms first, second, third, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms may be only used to distinguishone element, component, region, layer or section from another region,layer or section. Terms such as “first,” “second,” and other numericalterms when used herein do not imply a sequence or order unless clearlyindicated by the context. Thus, a first element, component, region,layer or section discussed below could be termed a second element,component, region, layer or section without departing from the teachingsof the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,”“lower,” “above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

With reference to FIG. 1, a seat assembly 10 is provided. The seatassembly 10 may include a seatback 12, a seat bottom 14, and one or moreseat track assemblies 16. In some implementations, the seat assembly 10is adjustably mounted to a vehicle (not shown), such as an automobile.For example, a reclining mechanism (not shown) may pivotably move theseatback 12 relative to the seat bottom 14, and the seat trackassemblies 16 may translatably move the seat bottom 14 to a certainposition relative to a vehicle floor pan (not shown). Accordingly, auser may selectively change the orientation of the seatback 12 relativeto the seat bottom 14 using the reclining mechanism (not shown), and theposition of the seat assembly 10 relative to the vehicle floor pan usingthe pair of seat track assemblies 16.

Each seat track assembly 16 may include a lower track 20, an upper track22, and an adjustment assembly 24. The adjustment assembly 24 may befixedly attached to a portion of the upper track 22 by one or moremechanical fasteners 26 (e.g., bolts, screws, rivets, etc.). In certainimplementations the upper track 22 defines one or more cutouts (notshown) to accommodate the adjustment assembly 24.

The lower track 20 may be fixedly attached to a portion of the vehicleusing one or more mechanical fasteners 28 (e.g., bolts, screws, rivets,etc.), or any other suitable fastening technique, and may define an axisA1. The lower track 20 may define a U-shaped profile extending in adirection substantially parallel to the axis A1 such that walls of thelower track 20 cooperate to define a central lower channel 30.

The upper track 22 may be fixedly attached to a portion of the seatbottom 14 using one or more mechanical fasteners 32 (e.g., bolts,screws, rivets, etc.), or any other suitable fastening technique. Theupper track 22 may define a U-shaped profile extending in a directionsubstantially parallel to the axis A1 such that walls of the upper track22 cooperate to define a central upper channel 34.

In an assembled configuration, as shown, the lower track 20 may supportthe upper track 22 for translation along the axis A1, such that theupper track 22 translates relative to the vehicle. For example, thelower track 20 may slidably support the upper track 22 for translationalong the axis A1. The upper track 22 may translate relative to thelower track 20 to permit selective movement of the seatback 12 and theseat bottom 14 relative to the vehicle. Movement of the upper track 22relative to the lower track 20 may be facilitated by a carriage assembly50, including two pairs of ball-cage assemblies 52, which may be: (i)secured to the upper track 22 and/or the adjustment assembly 24, and(ii) at least partially received within the central lower channel 30 ofthe lower track 20.

With reference to FIG. 2, the adjustment assembly 24 may include adriver assembly 54, a spindle screw or lead screw 56, and an adjustmentsubassembly 58. In an assembled configuration, a portion of theadjustment assembly 24 may be secured relative to the vehicle andanother portion of the adjustment assembly 24 may be secured relative tothe upper track 22 to facilitate movement of the seatback 12 and theseat bottom 14 relative to the vehicle. For example, the spindle screw56 may be secured to the lower track 20 and/or to the vehicle floor,while the adjustment subassembly 58 may be secured to the upper track22. Accordingly, movement of the adjustment subassembly 58 relative tothe spindle screw 56 causes the fore and aft movement of the upper track22 and the seat bottom 14 relative to the lower track 20 and ultimatelyto the vehicle floor.

The driver assembly 54 may include an electric bi-directional motor andtwo flex drive shafts that transfer the speed and torque from theelectric motor to the adjustment subassembly 58 to cause the movement ofthe adjustment subassembly 58 along the spindle screw 56 length and,thus, the fore-and-aft movement of the seat assembly 10 (FIG. 1),relative to the vehicle floor.

The spindle screw 56 may include a front end 62 and a rear end 64. Insome implementations, the spindle screw 56 may define a substantiallycylindrical rod defining an axis A2 extending from the front end 62 tothe rear end 64 and having an outer thread 66 extending along and aboutthe axis A2 from the front end 62 to the rear end 64. In an assembledconfiguration, the spindle screw 56 may be disposed within one or bothof the central lower channel 30 of the lower track 20 and the centralupper channel 34 of the upper track 22 such that the axis A2 issubstantially parallel to the axis A1 (FIG. 1). The front end 62 andrear end 64 may be secured relative to the lower track 20 and/or to thevehicle floor through the studs rigidly mounted on the lower track 20.For example, the front end 62 may be supported by a front spindlebracket 68 that is secured to the lower track 20 and/or to the vehiclefloor, and the rear end 64 may be supported by a rear spindle bracket 70that is also secured to the lower track 20 and/or to the vehicle floor.

With reference to at least FIG. 3, the adjustment subassembly 58 mayinclude a support frame 74, a housing assembly 76, a pair of bearingbushings 78, a first gear or cylindrical worm 80 having a helical outerthread 82 in mesh with external teeth 84 of a second gear or envelopingworm 86, a spindle nut integrally formed with the second gear 86 andhaving an internal thread 90, and the spindle screw 56 with the outerthread 66 (FIG. 2) engaging the internal thread 90 of the spindle nut.The first and second gears 80, 86 may be collectively referred to as agear system or a gear assembly.

The support frame 74 may define a U-shape. The support frame 74 mayinclude a base 100, a pair of walls 102 extending substantiallyperpendicular to the base 100 on opposing ends of the base 100, and apair of flanges 104 extending substantially perpendicular to the pair ofwalls 102, respectively, and substantially parallel to the base 100. Thebase 100, walls 102, and flanges 104 may be integrally formed. The base100 and walls 102 may cooperate to define an interior region 106. Thepair of walls 102 may define a respective pair of wall apertures 108.The pair of flanges 104, may define a respective pair of flangeapertures 110.

The housing assembly 76 may include a gearbox 114, a first cover shell116, and a second cover shell 118 (also referred to as the “pair ofcover shells 116, 118”). The first and second cover shells 116, 118 maybe geometrically mirrored. The first and second cover shells 116, 118may define respective first and second shell apertures 120, 122. Thefirst and second cover shells 116, 118 may define first and second shellinterior regions 124, 126, respectively.

The first and second cover shells 116, 118 may be formed from aresilient material having noise and vibration dampening characteristics.In some implementations, the first and second cover shells 116, 118 maybe formed from a polymer such as rubber, for example. The use of rubbercover shells 116, 118, in compression against the walls 102 of thesupport frame 74, may increase the damping capability of the adjustmentsubassembly 58 in the process of vibration transmission to the seatstructure.

The gearbox 114 may be formed from aluminum-zinc alloy die-castingmaterial. The gearbox 114 may include a first part or portion 130 and asecond part or portion 132. Each of the first and second portions 130,132 may define a longitudinal recess 134, a peripheral recess 136, andan aperture 138. Each of the first and second portions 130, 132 furtherincludes a curved mating surface 140. In an assembled state, the curvedmating surfaces 140 of the first and second portions 130, 132 are incontact with each other, the longitudinal recesses 134 cooperate todefine a longitudinal passage, and the peripheral recesses 136 cooperateto define a peripheral receptacle. The gearbox 114 may be secured in theassembled configuration by a plurality of fasteners 142 (e.g., screws,bolts, rivets, etc.). Various implementations of gearboxes are describedin greater detail below.

The cylindrical worm 80 may define an axis of rotation A3 extending froma first end 150 to a second end 152. The helical outer thread 82 may bedisposed about the axis of rotation A3 between the first and second ends150, 152. In various implementations, the cylindrical worm 80 may bemanufactured by an injection molding process from a plastic materialsuch as PEEK 450G. The cylindrical worn 80 may be rotatably supported bythe housing assembly 76. For example, the first end 150 of thecylindrical worm 80 may be rotatably disposed within the aperture 138 ofthe first portion 130 of the gearbox 114 and the second end 152 of thecylindrical worm 80 may be rotatably disposed within the aperture 138 ofthe second portion 132 of the gearbox 114.

The enveloping worm 86 may define an axis of rotation A4 extending froma first end 154 to a second end 156. The internal thread 90 and theexternal teeth 84 may be disposed about the axis of rotation A4. Thebearing bushings 78 may include respective through-holes 160 thatreceive outer bearing surfaces 162 of enveloping worm 86. In theassembled configuration, the enveloping worm 86 and the bearing bushings78 may be disposed at least partially within the longitudinal passage(formed by longitudinal recesses 134) of the gearbox 114. The envelopingworm 86 may be disposed between the bearing bushings 78 and rotatablewith respect to the bearing bushings 78. The bearing bushings 78 may berotatably fixed with respect to the gearbox 114 by engagement ofradially-extending tabs 164 of the bearing bushings 78 with the gearbox114.

In the assembled configuration, the gearbox 114 is disposed between thecover shells 116, 118 and at least partially within the shell interiorregions 124, 126. The housing assembly 76, which includes the gearbox114 and cover shells 116, 118, is disposed at least partially within theinterior region 106 of the support frame 74. The spindle screw 56 (FIG.2) extends through a gear passage 166 of the enveloping worm 86, thethrough-holes 160 of the bearing bushings 78, the longitudinal passage(formed by the longitudinal recesses 134), the first and second shellapertures 120, 122, and the wall apertures 108. The internal thread 90of the enveloping worm 86 is threaded to the outer thread 66 (FIG. 2) ofthe spindle screw 56 (FIG. 2), and the external teeth 84 of theenveloping worm 86 are meshed with the helical outer thread 82 of thecylindrical worm 80.

The axis of rotation A4 of the enveloping worm 86 may be substantiallyparallel to and aligned with the axis A2 of the spindle screw 56. Theaxis of rotation A3 of the cylindrical worm 80 may be substantiallyperpendicular to the axes A2 and A4. In the assembled configuration, theadjustment subassembly 58 may be disposed within the central lowerchannel 30 of the lower track 20 and/or the central upper channel 34 ofthe upper track 22. The axes A2, A4 may be substantially parallel to andaligned with the axis A1.

Gearboxes

A gearbox according to the principles of the present disclosure may haveone or more features to facilitate alignment of the two portions of thegearbox, distribute stresses, increase ease of assembly, improveaccuracy of assembly, accommodate manufacturing tolerances, reduce oreliminate vibration and/or noise during use, and/or provide modularityto accommodate variety of gear assembly configurations, as will bedescribed in greater detail below. More specifically, a gearboxaccording to the principles of the present disclosure may include curvedmating surfaces, one or more preassembly join stop features, and/or anelastic layer, each of which is described in greater detail below.

Additionally, any of the gearboxes may be open-type gearboxes orclose-type gearboxes. Close-type gearbox include a wall, such as a topwall, that at least partially encloses a worm gear. Close-type gearboxesmay be used to reduce or eliminate contamination of gear systems insidethe gearbox and/or eliminate noise during use of the gear system. Insome implementations, a close-type gearbox may be used to facilitatenoise reduction in an ultra-high speed gear system, which operates at ahigher mesh frequency compared to lower speed gear systems. An exampleof a close-type gearbox is shown in FIGS. 4A-4E. Open-type gearboxes maybe used in applications with low or no expected contamination and/or lowexpected noise. In some implementations, an open-type gearbox may beused with a comfort-speed or a high speed gear system that is notexpected to emit significant noise during use. Examples of open-typegearboxes are shown in FIGS. 5A-7E, 9-11B, and 15A-19D.

The first and second portions of the gearbox may be manufactured in adie-casting process. The gearbox may comprise casting metal, such as analuminum zinc alloy. The gearboxes may be assembled with various typesof discrete or integral fasteners.

Curved Mating Surfaces

A two-part gearbox in accordance with the principles of the presentdisclosure may include curved mating surfaces. The mating curvedsurfaces may be defined by a portion of a three-dimensional curve, suchas an ellipsoid, a cone, or a sphere. The two-part gearbox includes afirst portion with a first curved mating surface and a second portionwith a second curved mating surface. One of the mating surfaces isconvex, while the other mating surface is concave. The mating surfacesmay define the substantially the same shape, with equal and oppositecurvature.

The mating surfaces may be self-centering in at least two orthogonaldirections. In certain implementations, the mating surfaces areself-centering in three orthogonal directions (e.g., spherical matingsurfaces). Accordingly, the curved mating surfaces may facilitateefficient assembly and preassembly with improved accuracy. Moreover,gearboxes having the self-centering mating surfaces may be free ofcertain other alignment features. In addition to facilitating alignment,the curved mating surfaces also increase surface area contact betweenthe two gearbox portions, thereby improving a distribution of shearstress in the gearbox assembly during normal and/or shock loadingconditions.

Referring to FIGS. 4A-4E, a gearbox 400 in accordance with theprinciples of the present disclosure is provided. The gearbox 400includes a first part or portion 402 and a second part or portion 404. Aboundary or joint 406 between the first and second portions 402, 404defines a portion of an ellipsoid 408. The ellipsoid 408 may define afirst or vertical radius and a second or horizontal radius. In certainimplementations, the first radius is in a range of 190 mm to 200 mm andthe second radius is in a range of 240 to 250 mm.

The first portion 402 includes a first body 410. The first body 410includes a first exterior surface 412 and a first mating surface orcurved surface 414. The first mating surface 414 is concave such that itcurves inward 415, away from the second portion 404. The second portion404 includes a second body 416. The second body 416 includes a secondexterior surface 418 and a second mating surface or curved surface 420.The second mating surface 420 is convex such that it curves outward 421,toward the first portion 402. Curvatures of the first and second matingsurfaces 414, 420 are substantially equal and opposite. Morespecifically, the first mating surface 414 is defined by a portion of aradial-outside 422 of the ellipsoid 408 and the second mating surface420 is defined by a portion of a radial-inside 424 of the ellipsoid 408.

During pre-assembly of the gearbox 400, the mating surfaces 414, 420 maybe configured to have a self-centering effect on the first and secondportions 402, 404 to facilitate alignment of the first and secondportions 402, 404. Prior to alignment during preassembly, the matingsurfaces 414, 420 may be in less than complete contact (i.e., gaps maybe present between the first and second mating surfaces 414, 420). Oneor both of the portions 402, 404 may be moved along a first orthogonaldirection 426 and/or a second orthogonal direction 428 with respect tothe other of the portions 402, 404 until the portions 402, 404 slideinto alignment. This may be referred to as bi-directionalself-centering. When the portions 402, 404 are aligned, the first andsecond mating surfaces 414, 420 may be in substantially continuouscontact at the boundary 406.

The first body 410 of the first portion 402 defines a first longitudinalrecess 440 and a first peripheral recess 442. The first longitudinalrecess 440 and the first peripheral recess 442 are in fluidcommunication. The first body 410 includes a first wall 444. The firstwall 444 at least partially defines the first peripheral recess 442. Thefirst wall 444 may be partially cylindrical.

The second body 416 of the second portion 404 defines a secondlongitudinal recess 446 and a second peripheral recess 448. The secondlongitudinal recess 446 and the second peripheral recess 448 are influid communication. The second body 416 includes a second wall 450. Thesecond wall 450 at least partially defines the second peripheral recess448. The second wall 450 may be partially cylindrical.

The first and second longitudinal recesses 440, 446 cooperate to definea longitudinal passage 452 (FIGS. 4B-4C). The longitudinal passage 452may extend continuously between first and second sides of the gearbox400. When the gearbox 400 is assembled in a vehicle seat adjustmentassembly, the longitudinal passage 452 may be aligned with axes of alower track, spindle screw, and second gear (e.g., lower track 20,spindle screw 56, and second gear 86 of FIGS. 1-3). The longitudinalpassage 452 may be configured to receive a second gear, a portion of aspindle screw, and bearing (e.g., second gear 86, spindle screw 56, andbearing bushings 78 of FIGS. 1-3).

The first and second peripheral recesses 442, 448 cooperate to define aperipheral receptacle 454 (FIG. 4C). The peripheral receptacle 454 ispartially enclosed by the first and second walls 444, 450. Accordingly,gearbox 400 may be described as a close-type gearbox. The peripheralreceptacle 454 may be configured to receive a first gear (e.g., firstgear 80 of FIGS. 1-3). The first and second bodies 410, 416 may definerespective first and second apertures 460, 462. The first and secondapertures 460, 462 may be configured to support first and second bearingsurfaces of a first gear (e.g., first gear 80 of FIGS. 1-3).

The first body 410 of the first portion 402 may define a plurality ofthird apertures 464. The second body 416 of the second portion 404 maydefine a plurality of fourth apertures 466. When the gearbox 400 isassembled, the third apertures 464 are axially aligned with the fourthapertures 466, respectively. The apertures 444, 466 may be configured toreceive a plurality of fasteners, as will be described in greater detailbelow (see discussion accompanying FIGS. 12A-14D) to retain the gearbox400 in the assembled configuration.

The gearbox 400 may further include a pair of pins 470 and a pair ofreceptacles 472. In the implementation shown, the pins 470 project fromthe second mating surface 420 of the second portion 404 and thereceptacles 472 are defined in the first body 410 of the first portion402. However, in other implementations, a first portion may include thepins while a second portion includes the receptacles. In someimplementations, first and second portions may each include one pin andone receptacle.

The receptacles 472 may be blind holes. The pins 470 may befrusto-conical such that they have a largest diameter adjacent to thesecond body 416. The receptacles 472 may be frusto-conical such thatthey have a largest diameter at the first mating surface 414. Thereceptacles 472 may be configured receive respective pins 470 duringpreassembly of the gearbox 400. The pins 470 may be disposed in thereceptacles 472 when the gearbox 400 is in the assembled configuration.

In various implementations, the gearbox 400 may further include one ormore preassembly join stop features. For example, the gearbox 400 mayinclude annular projections 480 to be received in annular depressions482. The annular projections 480 may be coaxial with the pins 470 andthe annular depressions 482 may be coaxial with the receptacles 472. Agearbox according to the principles of the present disclosure may befree of preassembly join stop features, include a single stop feature,include two stop features (e.g., the pair of annular projections 480 andthe pair of annular depressions 482), as shown, or include more than twostop features. Pre-assembly join stop features are described in greaterdetail below in the discussion accompanying FIGS. 8A-10.

With reference to FIGS. 5A-5B, another gearbox 400 a is illustrated. Thestructure and function of the gearbox 400 a may be substantially similarto that of the gearbox 400, apart from any exceptions described belowand/or otherwise shown in the figures. Accordingly, the structure and/orfunction of similar features will not be described again in detail. Inaddition, like reference numerals are used hereinafter and in thedrawings to identify like features, while like reference numeralscontaining letter extensions (i.e., “a”) are used to identify thosefeatures that have been modified.

The gearbox 400 a includes a first part or portion 402 a and a secondpart or portion 404 a. A boundary or joint 406 a between the first andsecond portions 402 a, 404 a defines a portion of an ellipsoid 408.

The first portion 402 a includes a first body 410 a. The first body 410a includes a first exterior surface 412 a and a first mating surface orcurved surface 414 a. The first mating surface 414 a is concave. Thesecond portion 404 a includes a second body 416 a. The second body 416 aincludes a second exterior surface 418 a and a second mating surface orcurved surface 420 a. The second mating surface 420 a is convex.

The first body 410 a of the first portion 402 a defines a firstlongitudinal recess 440 and a first peripheral recess 442 a. The firstlongitudinal recess 440 and the first peripheral recess 442 a are influid communication. The second body 416 a of the second portion 404 adefines a second longitudinal recess 446 and a second peripheral recess448 a. The second longitudinal recess 446 and the second peripheralrecess 448 a are in fluid communication.

The first and second longitudinal recesses 440, 446 cooperate to definea longitudinal passage 452 (FIG. 5A). The first and second peripheralrecesses 442 a, 448 a cooperate to define a peripheral receptacle 454 a(FIG. 5A). The peripheral receptacle 454 a is open to an exterior region500 of the gearbox 400 a at a peripheral opening 502 defined by thefirst and second bodies 410 a, 416 a when the gearbox 400 a is in theassembled configuration. Accordingly, the gearbox 400 a may be describedas an open-type gearbox. The peripheral receptacle 454 a may beconfigured to at least partially receive a first gear (e.g., first gear80 of FIGS. 1-3), such as in first and second apertures 460, 462 thatsupport first and second bearing surfaces of the first gear. A portionof the first gear may project from the gearbox 400 a through theperipheral opening 502.

The gearbox 400 a may further include third and fourth apertures 464,466 for receiving fasteners, pins 470 and receptacles 472, and annularprojections and depressions 480, 482 as shown and as described above inthe discussion accompanying FIGS. 4A-4E.

Referring to FIGS. 6A-6D, another gearbox 400 b is illustrated. Thestructure and function of the gearbox 400 b may be substantially similarto that of the gearbox 400 a, apart from any exceptions described belowand/or otherwise shown in the figures. Accordingly, the structure and/orfunction of similar features will not be described again in detail. Inaddition, like reference numerals are used hereinafter and in thedrawings to identify like features, while like reference numeralscontaining letter extensions (i.e., “b”) are used to identify thosefeatures that have been modified.

The gearbox 400 b includes a first part or portion 402 b and a secondpart or portion 404 b. A boundary or joint 406 b between the first andsecond portions 402 b, 404 b defines a portion of a cone 600. In certainimplementations, the cone 600 may define an opening angle ranging from165° to 172°.

The first portion 402 b includes a first body 410 b. The first body 410b includes a first exterior surface 412 a and a first mating surface orcurved surface 414 b. The first mating surface 414 b is concave suchthat it curves inward 415, away from the second portion 404 b. Thesecond portion 404 b includes a second body 416 b. The second body 416 bincludes a second exterior surface 418 a and a second mating surface orcurved surface 420 b. The second mating surface 420 b is convex suchthat it curves outward 421, toward the first portion 402 b. Curvaturesof the first and second mating surfaces 414 b, 420 b are substantiallyequal and opposite.

During pre-assembly of the gearbox, the mating surfaces 414 b, 420 b maybe configured to have a self-centering effect on the first and secondportions 402 b, 404 b to facilitate alignment of the first and secondportions 402 b, 404 b. Prior to alignment during preassembly, the matingsurfaces 414 b, 420 b may be in less than complete contact (i.e., theremay be gaps between the first and second mating surfaces 414 b, 420 b).One or both of the portions 402 b, 404 b may be moved along a firstorthogonal direction 426 and/or a second orthogonal direction 430 withrespect to the other of the portions 402 b, 404 b until the portions 402b, 404 b slide into alignment. This may be referred to as bi-directionalself-centering. When the portions 402 b, 404 b are aligned, the firstand second mating surfaces 414 b, 420 b may be in substantiallycontinuous contact at the boundary 406 b.

The first body 410 b of the first portion 402 b defines a firstlongitudinal recess 440 and a first peripheral recess 442 a. The firstlongitudinal recess 440 and the first peripheral recess 442 a are influid communication. The second body 416 b of the second portion 404 bdefines a second longitudinal recess 446 and a second peripheral recess448 a. The second longitudinal recess 446 and the second peripheralrecess 448 a are in fluid communication. The first and secondlongitudinal recesses 440, 446 cooperate to define a longitudinalpassage 452 (FIG. 6A-6B). The first and second peripheral recesses 442a, 448 a cooperate to define a peripheral receptacle 454 a (FIG. 6A).While the gearbox 400 a is shown as an open-type gearbox, in otherimplementations, it may include walls similar or identical to the walls444, 450 of the gearbox 400 (FIGS. 4A-4E) and be a close-type gearbox.

The gearbox 400 b may further include third and fourth apertures 464,466 for receiving fasteners, pins 470 and receptacles 472, and annularprojections and depressions 480, 482 as shown and as described above inthe discussion accompanying FIGS. 4A-4E.

Referring to FIGS. 7A-7E, another gearbox 400 c is illustrated. Thestructure and function of the gearbox 400 c may be substantially similarto that of the gearbox 400 a, apart from any exceptions described belowand/or otherwise shown in the figures. Accordingly, the structure and/orfunction of similar features will not be described again in detail. Inaddition, like reference numerals are used hereinafter and in thedrawings to identify like features, while like reference numeralscontaining letter extensions (i.e., “c”) are used to identify thosefeatures that have been modified.

The gearbox 400 c includes a first part or portion 402 c and a secondpart or portion 404 c. A boundary or joint 406 c between the first andsecond portions 402 c, 404 c defines a portion of a sphere 700. Incertain implementations, the sphere 700 may define a radius in a rangeof 190 mm to 200 mm.

The first portion 402 c includes a first body 410 c. The first body 410c includes a first exterior surface 412 a and a first mating surface orcurved surface 414 c. The first mating surface 414 c is concave suchthat it curves inward 415, away from the second portion 404 c. Thesecond portion 404 c includes a second body 416 c. The second body 416 cincludes a second exterior surface 418 a and a second mating surface orcurved surface 42 bc. The second mating surface 420 c is convex suchthat it curves outward 421, toward the first portion 402 c. Curvaturesof the first and second mating surfaces 414 c, 420 c are substantiallyequal and opposite.

During pre-assembly of the gearbox, the mating surfaces 414 c, 420 c maybe configured to have a self-centering effect on the first and secondportions 402 c, 404 c to facilitate alignment of the first and secondportions 402 c, 404 c. Prior to alignment during preassembly, the matingsurfaces 414 c, 420 c may be in less than complete contact (i.e., theremay be gaps between the first and second mating surfaces 414 c, 420 c).One or both of the portions 402 c, 404 c may be moved along a firstorthogonal direction 426, a second orthogonal direction 430, and/or athird orthogonal direction 702 with respect to the other of the portions402 c, 404 c until the portions 402 c, 404 c slide into alignment. Thismay be referred to as three-directional self-centering. When theportions 402 c, 404 c are aligned, the first and second mating surfaces414 c, 420 c may be in substantially continuous contact at the boundary406 c.

The first body 410 c of the first portion 402 c defines a firstlongitudinal recess 440 and a first peripheral recess 442 a. The firstlongitudinal recess 440 and the first peripheral recess 442 a are influid communication. The second body 416 c of the second portion 404 cdefines a second longitudinal recess 446 and a second peripheral recess448 a. The second longitudinal recess 446 and the second peripheralrecess 448 a are in fluid communication. The first and secondlongitudinal recesses 440, 446 cooperate to define a longitudinalpassage 452 (FIG. 7B-7C). The first and second peripheral recesses 442a, 448 a cooperate to define a peripheral receptacle 454 a (FIG. 7B).While the gearbox 400 c is shown as being an open-type gearbox, in otherimplementations, the gearbox 400 c may include walls similar oridentical to the walls 444, 446 of the gearbox 400 (FIGS. 4A-4E) and bea close-type gearbox.

The gearbox 400 c may further include third and fourth apertures 464,466 for receiving fasteners, pins 470 and receptacles 472, and annularprojections and depressions 480, 482 as shown and as described above inthe discussion accompanying FIGS. 4A-4E.

Preassembly Join Stop Features

Gearboxes according to the principles of the present disclosure mayinclude one or more features to facilitate preassembly and offerflexibility to accommodate manufacturing tolerances. Gearboxes mayinclude a single preassembly join stop feature, a double preassemblyjoin stop feature, or more than two preassembly join stop features. Invarious implementations, a gearbox may be free of preassembly join stopfeatures.

Referring to FIG. 8A, a portion of the second body 416 a of the gearbox400 a of FIG. 5A is shown. The portion includes the pin 470 and theannular projection 480. In various implementations, the pin 470 and theannular projection 480 may be integrally formed with the second body 420a.

The pin 470 projects from the second mating surface 420 a. The pin 470may have a frusto-conical shape such that it has a larger diameter at aproximal end or base, closer to the second mating surface 420 a and asmaller diameter at a distal end 800 further from the second matingsurface 420 a. The pin 470 includes a first joint surface 802 that isfrusto-conical.

The annular projection 480 may have a larger radius than the pin 470 andextend circumferentially around the base of the pin 470. The annularprojection may extend axially from the second mating surface 420 atoward the distal end 800 of the pin 470. However, the annularprojection 480 may extend axially along only a portion of a length ofthe pin 470. The annular projection 480 includes a second joint surface804.

With reference to FIG. 8B, the first body 410 a includes the receptacle472 and the annular depression 482. The receptacle 472 may be defined bythe first mating surface 414 a. The receptacle 472 may have afrusto-conical shape such that it has a larger diameter at a proximalend 806 at the first mating surface 414 a and a smaller diameter at adistal end 808 offset from the first mating surface 414 a. Thereceptacle 472 includes a third joint surface 810 that isfrusto-conical.

The annular depression 482 may have a larger radius than the receptacle472 and extend circumferentially around a portion of the receptacle. Theannular depression may extend axially from the first mating surface 414a toward the distal end 808 of the receptacle 472. However, the annulardepression 482 may extend axially along only a portion of a length ofthe receptacle 472. The annular depression 482 may include a fourthjoint surface 812.

When the gearbox 400 a (FIG. 5A) is in an assembled or preassembledconfiguration, the pin 470 is received in the receptacle 472. The firstjoint surface 802 of the pin 470 may engage the third joint surface 810of the receptacle 472. The annular projection 480 is received in theannular depression 482. The second joint surface 814 of the annularprojection 480 may engage the fourth joint surface 812 of the annulardepression 482. Collectively, the annular projection 480 and the annulardepression 482 may be referred to as a preassembly join stop feature.

Returning to FIG. 5A, the gearbox 400 a may include two preassembly joinstop features, such as the two pairs of annular projections anddepressions 480, 482. That is, the gearbox 400 a may have double joinstop features. The first portion 402 a may include the receptacles 472and the annular depressions 482 and the second portion 404 a may includethe pins 470 and the annular projections 480, as shown. In various otherimplementations, a first portion may include pins and projections whilea second portion includes receptacles and depressions. In various otherimplementations, both first and second portions may include pins,annular projections, receptacles, and annular depressions.

With reference to FIG. 9, another gearbox 400 d is illustrated. Thestructure and function of the gearbox 400 d may be substantially similarto that of the gearbox 400 a, apart from any exceptions described belowand/or otherwise shown in the figures. Accordingly, the structure and/orfunction of similar features will not be described again in detail. Inaddition, like reference numerals are used hereinafter and in thedrawings to identify like features, while like reference numeralscontaining letter extensions (i.e., “d”) are used to identify thosefeatures that have been modified.

The gearbox 400 d includes a first part or portion 402 d and a secondpart or portion 404 d. A boundary or joint (see, e.g., boundary 406 a ofFIG. 5A) between the first and second portions 402 d, 404 d defines athree-dimensional curve, such as a portion of one of an ellipsoid, acone, or a sphere.

The first portion 402 d includes a first body 410 d. The first body 410d includes a first exterior surface 412 a and a first mating surface orcurved surface 414 d. The second portion 404 d includes a second body416 d. The second body 416 d includes a second exterior surface 418 aand a second mating surface or curved surface 420 d. One of the firstand second mating surfaces 414 d, 420 d is concave and the other of thefirst and second mating surfaces 414 d, 420 d is convex.

The first body 410 d of the first portion 402 d defines a firstlongitudinal recess 440 and a first peripheral recess 442 a. The firstlongitudinal recess 440 and the first peripheral recess 442 a are influid communication. The second body 416 d of the second portion 404 ddefines a second longitudinal recess 446 and a second peripheral recess448 a. The second longitudinal recess 446 and the second peripheralrecess 448 a are in fluid communication.

The first and second longitudinal recesses 440, 446 cooperate to definea longitudinal passage (see, e.g., longitudinal passage 452 of FIG. 5A).The first and second peripheral recesses 442 a, 448 a cooperate todefine a peripheral receptacle (see e.g., peripheral receptacle 454 a ofFIG. 5A). While the gearbox 400 d is shown as being an open-typegearbox, the gearbox 400 d may further include walls similar to thewalls 444, 446 of the gearbox 400 of FIGS. 4A-4E and be a close-typegearbox. The gearbox 400 d may further include third and fourthapertures 464, 466 for receiving fasteners.

The second portion 404 d may include a pin 470 and a pin 470 d. Anannular projection 480 may extend around a portion of the pin 470, asdescribed above in the discussion accompanying FIGS. 8A-8B. The pin 470d may extend from the second mating surface 420 d between a proximal endor base 900 and a distal end 902. The pin 470 d may include a firstjoint surface 904 extending between the proximal end 900 and the distalend 902.

The first portion 402 d may include a receptacle 472 and a receptacle472 d. An annular depression 482 may extend around a portion of thereceptacle 472, as described above in the discussion accompanying FIGS.8A-8B. The receptacle 472 d may extend into the first mating surface 414d from a proximal end 906 to a distal end (not shown). The receptacle472 d may include a second joint surface 910 extending between theproximal end 906 and the distal end.

When the gearbox 400 d is in an assembled or preassembled configuration,the receptacle 472 d receives the pin 470 d. The first joint surface 904may engage the second joint surface 910. The gearbox 400 d includes asingle preassembly join stop feature (e.g., the annular projection anddepression 480, 482). Accordingly, the gearbox 400 d may be asymmetricabout a plane that extends through a center axis 912 and between a top914 and bottom 916 of the gearbox 400 d. Although the annular projectionand depression 480, 482 are shown on a first side 918 of the plane, invarious other implementations, the annular projection and depression480, 482 may alternatively be on a second side 920 of the plane.

With reference to FIG. 10, another gearbox 400 e is illustrated. Thestructure and function of the gearbox 400 e may be substantially similarto that of the gearbox 400 d, apart from any exceptions described belowand/or otherwise shown in the figures. Accordingly, the structure and/orfunction of similar features will not be described again in detail. Inaddition, like reference numerals are used hereinafter and in thedrawings to identify like features, while like reference numeralscontaining letter extensions (i.e., “e”) are used to identify thosefeatures that have been modified.

The gearbox 400 e includes a first part or portion 402 e and a secondpart or portion 404 e. A boundary or joint (see, e.g., boundary 406 a ofFIG. 5A) between the first and second portions 402 e, 404 e defines athree-dimensional curve, such as portion of one of an ellipsoid, a cone,or a sphere.

The first portion 402 d includes a first body 410 e. The first body 410e includes a first exterior surface 412 a and a first mating surface orcurved surface 414 e. The second portion 404 e includes a second body416 e. The second body 416 e includes a second exterior surface 418 aand a second mating surface or curved surface 420 e. One of the firstand second mating surfaces 414 e, 420 e is concave and the other of thefirst and second mating surfaces 414 e, 420 e is convex.

The first body 410 e of the first portion 402 e defines a firstlongitudinal recess 440 and a first peripheral recess 442 a. The firstlongitudinal recess 440 and the first peripheral recess 442 a are influid communication. The second body 416 e of the second portion 404 edefines a second longitudinal recess 446 and a second peripheral recess448 a. The second longitudinal recess 446 and the second peripheralrecess 448 a are in fluid communication.

The first and second longitudinal recesses 440, 446 cooperate to definea longitudinal passage (see, e.g., longitudinal passage 452 of FIG. 5A).The first and second peripheral recesses 442 a, 448 a cooperate todefine a peripheral receptacle (see e.g., peripheral receptacle 454 a ofFIG. 5A). While the gearbox 400 e is shown as an open-type gearbox, thegearbox 400 e may, in other implementations, further include wallssimilar or identical to the walls 444, 446 of the gearbox 400 of FIGS.4A-4E and be a close-type gearbox. The gearbox 400 e may also includethird and fourth apertures 464, 466 for receiving fasteners.

The second portion 404 e may include two pins 470 d. The first portion402 d may include two receptacles 472 d. When the gearbox 400 e is in anassembled or preassembled configuration, the receptacles 472 d receivethe pins 470 d, respectively. The gearbox 400 e may be symmetric about aplane that extends through a center axis 912 and between a top 914 andbottom 916 of the gearbox 400 e. The gearbox 400 e may be free ofpreassembly join stop features (e.g., one or more pairs of annularprojections and depressions 480, 482 as shown at least in FIGS. 8A-9).

Elastic Layer

A gearbox according to the principles of the present disclosure mayfurther include an elastic layer on a first mating surface and/or asecond mating surface. The elastic layer may, in variousimplementations, be referred to as a compensation elastic element. Theelastic layer facilitates accommodation of relatively largemanufacturing tolerances in the bodies of the gearbox portions, and moreparticularly in the mating surfaces. An elastic layer may beparticularly beneficial when used in a gearbox without preassembly joinstop features (see, e.g., gearbox 400 e of FIG. 10), but may also beused on gearboxes with preassembly join stop features (see, e.g.,gearboxes 400 a, 400 d). The elastic element may comprise an elasticmaterial, such as nitrile butadiene rubber, having a predefinedcompression hardness.

With reference to FIGS. 11A-11B, another gearbox 400 f is illustrated.The structure and function of the gearbox 400 f may be substantiallysimilar to that of the gearbox 400 e, apart from any exceptionsdescribed below and/or otherwise shown in the figures. Accordingly, thestructure and/or function of similar features will not be describedagain in detail. In addition, like reference numerals are usedhereinafter and in the drawings to identify like features, while likereference numerals containing letter extensions (i.e., “f”) are used toidentify those features that have been modified.

The gearbox 400 f includes a first part or portion 402 e and a secondpart or portion 404 f. A boundary or joint 406 f between the first andsecond portions 402 f, 404 f defines a three-dimensional curve, such asa portion of one of an ellipsoid, a cone, or a sphere. The first portion402 e includes a first body 410 e and the second portion 404 f includesa second body 416 e. The first and second bodies 410 e, 416 e includefirst and second mating surfaces 414 e, 420 e, respectively,

The second portion 404 f further includes an elastic layer 1100. Theelastic layer 1100 may be disposed on the second mating surface 420 e,such as directly on the second mating surface 420 e. The elastic layer1100 may be coupled to the second mating surface 420 e. The elasticlayer 1100 may have a substantially uniform thickness. For example, theelastic layer 1100 may define a thickness 1102 ranging from 1 mm to 1.5mm.

In other implementations, an elastic layer may additionally oralternatively be present on a first mating surface of a second portion.The use of an elastic layer, such as the elastic layer 1100, may beequally applicable to open-type or close-type gearboxes, having anymating surface curvature (e.g., ellipsoidal, conical, spherical), andany number of preassembly join stop features, including none.

Fasteners

A gearbox assembly according to the principles of the present disclosuremay include any of the gearboxes discussed above and a plurality offasteners. The fasteners may include screws, rivets, and/or bolts, byway of example. Rivets may be discrete components separate from thegearbox portions. Additionally or alternatively, one or both of thefirst and second portions may include built-in or integral rivets. Agearbox may include more than one type of fastener, such as anycombination of the fasteners described herein.

With reference to FIGS. 12A-12C, a gearbox assembly 1200 according tothe principles of the present disclosure is provided. The gearboxassembly 1200 includes the gearbox 400 a (see FIGS. 5A-5B andaccompanying discussion) and a plurality of fasteners 1202. Thefasteners 1202 may include screws, such as self-tapping screws. In someimplementations, the plurality of fasteners 1202 may include fourfasteners.

As best shown in FIG. 12B, each fastener 1202 may include a shaft 1204,a head 1206, and a thread 1208 extending along at least a portion of theshaft 1204. The shaft 1204 may extend through third and fourth apertures464, 466. The head 1206 may be disposed at least partially in acountersink 1210 in the second body 416 a such that an end 1212 of thehead 1206 is flush with at least a portion of the exterior surface 412 aof the second body 416 a. The thread 1208 may engage a surface 1214 ofthe third aperture 464 to couple the first and second portions 402 a,404 a to each other. In the assembled configuration, as shown in FIG.12C, the pins 470 and annular projections 480 may be disposed in thereceptacles 472 and annular depressions 482, respectively. In otherimplementations, an orientation of the screws 1202 may be reversed sothat the head 1206 engages the first body 410 a and the thread 1208engages the second body 416 a.

Although FIGS. 12A-12C depict the gearbox assembly 1200 including theopen-type gearbox having ellipsoidal mating surfaces and doublepreassembly join stop features, the use of screws is equally applicableto assemble other gearboxes according to the principles of the presentdisclosure. For example, a gearbox assembly may include screws and agearbox that (i) is open-type or close-type, (ii) has ellipsoidal,conical, spherical, or other three-dimensional curved mating surfaces,(iii) includes zero, one, two, or more than two preassembly join stopfeatures, and (iv) includes an elastic layer or is free of an elasticlayer.

Referring to FIGS. 13A-13D, a gearbox assembly 1300 according to theprinciples of the present disclosure is provided. The gearbox assembly1300 includes the gearbox 400 e (see FIG. 10 and accompanyingdiscussion) and a plurality of fasteners 1302. The fasteners 1302 mayinclude rivets. Prior to assembly and deformation, each of the rivetsmay be a distinct and separable component. In some implementations, theplurality of fasteners 1302 may include four rivets.

As best shown in FIG. 13C, each fastener 1302 may include a shaft 1304and a head 1306. The shaft 1304 may include a tail 1308 that isconfigured to be buckled, upset, or deformed to form a secondary head1308′, thereby transitioning the fastener 1302 from an undeformed stateto a deformed state. The shaft 1304 may extend through third and fourthapertures 464, 466. The head 1306 may be disposed at least partially ina countersink 1310 in the first body 410 e such that an end 1312 of thehead 1306 is flush with at least a portion of the first exterior surface412 a of the first body 410 e.

When the rivets 1302 are in the undeformed state, as shown in FIGS.13A-13C, the tail 1308 projects past the second exterior surface 418 a.When the rivets 1302 are in a deformed state, as shown in FIG. 12D, thesecondary head 1308′ may be disposed in a countersink 1314 on in thesecond body 416 e such that an end 1316 of the secondary head 1308′ isflush with the second exterior surface 418 a of the second body 416 e.In the deformed state, the rivets 1302 retain the gearbox 400 e in theassembled state by coupling the first and second portions 402 e and 404e to one another. In other implementations, an orientation of the rivets1302 may be reversed so that the head 1306 engages the second body 416 eand the secondary head 1308′ engages the first body 410 e.

Although FIGS. 13A-13D depict the gearbox assembly 1300 including theopen-type gearbox having ellipsoidal mating surfaces and being free ofpreassembly join stop features, the use of rivets is equally applicablefor assembly other gearboxes according to the principles of the presentdisclosure. For example, a gearbox assembly may include rivets and agearbox that (i) is open-type or close-type, (ii) has ellipsoidal,conical, spherical, or other three-dimensional curved mating surfaces,(iii) includes zero, one, two, or more than two preassembly join stopfeatures, and (iv) includes an elastic layer or is free of an elasticlayer.

Referring to FIGS. 14A-14D, a gearbox assembly 1400 according to theprinciples of the present disclosure is provided. The gearbox assembly1400 includes a gearbox 400 g having integral rivets. The structure andfunction of the gearbox 400 g may be substantially similar to that ofthe gearbox 400 a, apart from any exceptions described below and/orotherwise shown in the figures. Accordingly, the structure and/orfunction of similar features will not be described again in detail. Inaddition, like reference numerals are used hereinafter and in thedrawings to identify like features, while like reference numeralscontaining letter extensions (i.e., “g”) are used to identify thosefeatures that have been modified.

The gearbox 400 g includes a first part or portion 402 g and a secondpart or portion 404 g. A boundary or joint 406 g between the first andsecond portions 402 g, 404 g defines a portion of a three-dimensionalcurve, such as an ellipsoid, a cone, or a sphere. The first portion 402g includes a first body 410 g. The first body 410 g includes a firstexterior surface 412 a and a first mating surface or curved surface 414g. The second portion 404 g includes a second body 416 g. The secondbody 416 g includes a second exterior surface 418 a and a second matingsurface or curved surface 420 g. One of the first and second matingsurfaces 414 g, 420 g is concave and the other of the first and secondmating surfaces 414 g, 420 g is convex. Curvatures of the first andsecond mating surfaces 414 g, 420 g are substantially equal andopposite.

The first body 410 g of the first portion 402 g defines a firstlongitudinal recess 440 and a first peripheral recess 442 a. The firstlongitudinal recess 440 and the first peripheral recess 442 a are influid communication. The second body 416 g of the second portion 404 gdefines a second longitudinal recess 446 and a second peripheral recess448 a. The second longitudinal recess 446 and the second peripheralrecess 448 a are in fluid communication. The first and secondlongitudinal recesses 440, 446 cooperate to define a longitudinalpassage 452 (FIG. 14B). The first and second peripheral recesses 442 a,448 a cooperate to define a peripheral receptacle 454 a (FIG. 14B).While the gearbox 400 g is shown as being an open-type gearbox, thegearbox 400 g may, in other implementations, include walls similar oridentical to the walls 444, 446 of the gearbox 400 of FIGS. 4A-4E and bea close-type gearbox.

The second portion 404 g may include a first pair of integral rivets1402 and a second pair of integral rivets 1404. The first and secondpairs of rivets 1402, 1404 may be integrally formed with the second body416 g. The first and second pairs of rivets 1402, 1404 may extend fromthe second mating surface 420 g. The rivets 1402, 1404 may have circularor oval cross sections. In the implementation shown, the rivets 1402 ofthe first pair have circular cross sections and the rivets 1404 of thesecond pair have oval cross sections.

The first portion 402 g may include a first pair of rivet apertures 1406and a second pair of rivet apertures 1408. The first and second pairs ofrivet apertures may be defined in the first mating surface 414 g. Therivet apertures 1406, 1408 may have cross-sectional shapes that matchrespective cross-sectional shapes of the rivets 1402, 1404. In theembodiment shown, the rivet apertures 1406 of the first pair have acircular cross section and the rivet apertures 1408 of the second pairhave an oval cross section.

The first and second pairs of rivet apertures 1406, 1408 may beconfigured to receive the first and second pairs of rivets 1402, 1404,respectively. Prior to deformation, while in a preassembledconfiguration, the rivets 1402, 1404 may project beyond the firstexterior surface 412 a, as shown in FIGS. 14B-14C. In an assembledconfiguration, the rivets 1402, 1404 are buckled, upset, or deformedinto a deformed state. More specifically, respective first and secondtails 1410, 1412 (FIG. 14C) of the rivets 1402, 1404 of the first andsecond pairs may be deformed into respective first and second heads1410′, 1412′ (FIG. 14D). The first and second heads 1410′, 1412′ may bedisposed in respective first and second countersinks 1414, 1416 in thefirst exterior surface 414 a.

In other implementations, locations of the rivets and rivet aperturesmay be reversed so that the first portion includes rivets and the secondportion includes rivet apertures. In some implementations, both firstand second portions include rivets and rivet apertures.

Although FIGS. 14A-14D depict the gearbox assembly 1400 including theopen-type gearbox including double preassembly join stop features, theinclusion of integral rivets is equally applicable for assembly othergearboxes according to the principles of the present disclosure. Forexample, a gearbox assembly may include integral rivets on a gearboxthat (i) is open-type or close-type, (ii) has ellipsoidal, conical,spherical, or other three-dimensional curved mating surfaces, (iii)includes zero, one, two, or more than two preassembly join stopfeatures, and (iv) includes an elastic layer or is free of an elasticlayer.

Gear Assemblies

Gearboxes according to the principles of the present disclosure areconfigured to accommodate a variety of different gear assemblyconfigurations. In various implementations, a single universal gearboxis configured to accommodate a gear system including any combination ofthe following features. For example, gearboxes according to theprinciples of the present disclosure may (i) include a cross-axis singleenveloping gear system or a cross-axis helical gear system, (ii) benormal-strength or enhanced-strength, and (iii) be configured to operatewithin a comfort speed range, a high speed range, or a ultra-high speedrange.

A cross-axis single enveloping gear system includes a worm and a singleenveloping gear that are operably engaged and configured to rotate aboutperpendicular axes. The cross-axis single enveloping gear system may berobust and cost effective. A cross-axis helical gear system includes aworm and a helical gear that are operably engaged and configured torotate about perpendicular axes. A cross-axis helical gear system may beconfigured for quieter operation than a cross-axis single envelopinggear system.

A normal-strength power length adjuster system includes a leadscrewcapable of withstanding an axial forces of at least 19 kN. The leadscrewfor the normal-strength power length adjuster system may havetrapezoidal threads designated by Tr 8×3 (P1.5) (8 mm nominal diameter,3 mm lead, and 1.5 mm pitch). An enhanced-strength power length adjustersystem includes a lead screw capable of withstanding axial forces of atleast 25 kN. The leadscrew for the enhanced-strength power lengthadjuster system may have trapezoidal threads defined by Tr 9×3 (P1.5) (9mm nominal diameter, 3 mm lead, and 1.5 mm pitch).

Speed classifications may be achieved by a combination of gear ratio andmotor parameters (e.g., speed). In various implementations, a gearboxaccording to the principles of the present disclosure may accommodategear systems having linear adjustment speeds ranging from 17 mm/s to 85mm/s. In one implementation, a comfort speed system may be configured tohave an average linear adjusting speed ranging from 17 to 22 mm/s. Thecomfort speed system may have a maximum electrical motor rotationalspeed of about 3,900 rpm. The comfort speed system may have a gear ratioof at least 6.5:1. In another implementation, a high speed system may beconfigured to have an average linear adjustment speed ranging from 50mm/s to 55 mm/s. The high speed system may have a maximum electricalmotor rotational speed of about 4,900 rpm. The high speed system mayhave a gear ratio of at least 3.333:1. In yet another implementation, aultra-high speed system may be configured to have an average linearadjustment speed ranging from 80 mm/s to 85 mm/s, for example. Theultra-high speed system may have a maximum electrical motor rotationalspeed of about 6,900 rpm. The ultra-high speed system may have a gearratio of at least 2.6:1.

A universal gearbox according to the principles of the presentdisclosure may accommodate any combination of the above gear types,strengths, and speeds. That is, a single gearbox design may be providedin an assembly setting for subsequently accommodating any combination ofthe above options. Example implementations are described below.

Referring to FIGS. 15A-15D, an adjustment assembly 24 h according to theprinciples of the present disclosure is provided. The structure andfunction of the adjustment assembly 24 h may be substantially similar tothat of the adjustment assembly 24 (FIGS. 1-3), apart from anyexceptions described below and/or otherwise shown in the figures.Accordingly, the structure and/or function of similar features will notbe described again in detail. In addition, like reference numerals areused hereinafter and in the drawings to identify like features, whilelike reference numerals containing letter extensions (i.e., “h”) areused to identify those features that have been modified.

The adjustment assembly 24 h includes a spindle screw or lead screw 56 hhaving outer threads 66 h and an adjustment subassembly 58 h. Theadjustment subassembly 58 h includes a first gear or cylindrical worm 80h having helical outer threads 82 h, a second gear or enveloping worm 86h having external teeth 84 h and internal thread 90 h, a pair of bearingbushings 78, and a gearbox assembly 1200. The gearbox assembly 1200includes a gearbox 400 a and a plurality of fasteners 1202. The gearbox400 a includes first and second portions 402 a, 404 a. While not shown,the adjustment subassembly 58 h may further include a support frame(e.g., support frame 74 of FIGS. 1-3) and a pair of cover shells (e.g.,first and second cover shells 116, 118 of FIGS. 1-3). The adjustmentassembly 24 h may alternatively include any of the other gearboxassemblies described herein.

The threads 66 h of the spindle screw 56 h may be trapezoidal anddefined by Tr 9×3 (P1.5) (9 mm nominal diameter, 3 mm lead, and 1.5 mmpitch). The adjustment assembly 24 h may have a minimum axial strengthof 25 kN and be considered an enhanced-strength adjustment assembly. Thesecond gear 86 h may be a single enveloping worm gear. Therefore, theadjustment assembly 24 h may be considered to have a cross-axis singleenveloping gear system. The adjustment assembly 24 h may be configuredto be a comfort speed system via gear ratio and motor parameters.

With reference to FIGS. 16A-16E, an adjustment assembly 24 i accordingto the principles of the present disclosure is provided. The structureand function of the adjustment assembly 24 i may be substantiallysimilar to that of the adjustment assembly 24 (FIGS. 1-3), apart fromany exceptions described below and/or otherwise shown in the figures.Accordingly, the structure and/or function of similar features will notbe described again in detail. In addition, like reference numerals areused hereinafter and in the drawings to identify like features, whilelike reference numerals containing letter extensions (i.e., “i”) areused to identify those features that have been modified.

The adjustment assembly 24 i includes a spindle screw or lead screw 56 hhaving outer threads 66 h and an adjustment subassembly 58 i. Theadjustment subassembly 58 i includes a first gear or cylindrical worm 80i having helical outer threads 8 i 2, a second or helical gear 86 ihaving external teeth 84 i and internal thread 90 i, a pair of bearingbushings 78, a pair of washers 1600, a gearbox assembly 1200, a pair ofcover shells 116, 118, and a support frame 74. The gearbox assembly 1200includes a gearbox 400 a and a plurality of fasteners 1202. The gearbox400 a includes first and second portions 402 a, 404 a. the adjustmentassembly 24 i may alternatively include any of the other gearboxassemblies described herein.

The helical gear 86 i includes two cylindrical bearing surfaces 162 i.The external teeth 84 i extend in a space between the bearing surfaces162 i. Each washer 1600 is disposed on a respective one of the bearingsurfaces 1602 between the external teeth 84 i and a respective one ofthe bearing bushings 78. Each washer 1600 includes a retention feature,such as a tab 1604, that engages the helical gear 86. The tab 1604 mayreduce or prevent rotation of the washer 1600 with respect to thehelical gear 86 i.

The adjustment assembly 24 i includes the spindle screw 56 h having thethreads 66 h defined by Tr 9×3 (P1.5) (9 mm nominal diameter, 3 mm lead,and 1.5 mm pitch). The adjustment assembly 24 i may have a minimum axialstrength of 25 kN and be considered an enhanced-strength adjustmentassembly. The second gear 86 i may be a helical gear. Therefore, theadjustment assembly 24 i may be considered to have a cross-axis helicalgear system. The adjustment assembly 24 i may be configured to be acomfort speed system via gear ratios and motor parameters.

Referring to FIGS. 17A-17D, an adjustment assembly 24 j according to theprinciples of the present disclosure is provided. The structure andfunction of the adjustment assembly 24 j may be substantially similar tothat of the adjustment assembly 24 (FIGS. 1-3), apart from anyexceptions described below and/or otherwise shown in the figures.Accordingly, the structure and/or function of similar features will notbe described again in detail. In addition, like reference numerals areused hereinafter and in the drawings to identify like features, whilelike reference numerals containing letter extensions (i.e., “j”) areused to identify those features that have been modified.

The adjustment assembly 24 j includes a spindle screw or lead screw 56 jhaving outer threads 66 j and an adjustment subassembly 58 j. Theadjustment subassembly 58 j includes a first gear or cylindrical worm 80j having helical outer threads 82 j, a second gear or enveloping worm 86j having external teeth 84 j and internal thread 90 j, a pair of bearingbushings 78, and a gearbox assembly 1200. The gearbox assembly 1200includes a gearbox 400 a and a plurality of fasteners 1202. The gearbox400 a includes first and second portions 402 a, 404 a. The adjustmentassembly 24 j may alternatively include any of the other gearboxassemblies described herein. While not shown, the adjustment subassembly58 j may further include a support frame (e.g., support frame 74 ofFIGS. 1-3) and a pair of cover shells (e.g., first and second covershells 116, 118 of FIGS. 1-3).

The threads 66 j of the spindle screw 56 j may be trapezoidal anddefined by Tr 8×3 (P1.5) (8 mm nominal diameter, 3 mm lead, and 1.5 mmpitch). The adjustment assembly 24 j may have a minimum axial strengthof 19 kN and be considered a normal-strength adjustment assembly. Thesecond gear 86 j may be a single enveloping worm gear. Therefore, theadjustment assembly 24 j may be considered to have cross-axis singleenveloping orthogonal gear system. The adjustment assembly 24 j may beconfigured to be a high speed system via gear ratios and motor speed.

Referring to FIGS. 18A-18D, an adjustment assembly 24 k according to theprinciples of the present disclosure is provided. The structure andfunction of the adjustment assembly 24 k may be substantially similar tothat of the adjustment assembly 24 (FIGS. 1-3), apart from anyexceptions described below and/or otherwise shown in the figures.Accordingly, the structure and/or function of similar features will notbe described again in detail. In addition, like reference numerals areused hereinafter and in the drawings to identify like features, whilelike reference numerals containing letter extensions (i.e., “k”) areused to identify those features that have been modified.

The adjustment assembly 24 k includes a spindle screw or lead screw 56 jhaving outer threads 66 j and an adjustment subassembly 58 k. Theadjustment subassembly 58 k includes a first gear or cylindrical worm 80k having helical outer threads 82 k, a second gear or enveloping worm 86k having external teeth 84 j and internal thread 90 k, a pair of bearingbushings 78, a pair of washers 1600, and a gearbox assembly 1200. Thegearbox assembly 1200 includes a gearbox 400 a and a plurality offasteners 1202. The gearbox 400 a includes first and second portions 402a, 404 a. The adjustment assembly 24 k may alternatively include any ofthe other gearbox assemblies described here. While not shown, theadjustment subassembly 58 k may further include a support frame (e.g.,support frame 74 of FIGS. 1-3) a pair of cover shells (e.g., first andsecond cover shells 116, 118 of FIGS. 1-3).

The threads 66 j of the spindle screw 56 j may be trapezoidal anddefined by Tr 8×3 (P1.5) (8 mm nominal diameter, 3 mm lead, and 1.5 mmpitch). The adjustment assembly 24 j may have a minimum axial strengthof 19 kN and be considered a normal-strength adjustment assembly. Thesecond gear 86 k may be a single enveloping worm gear. Therefore, theadjustment assembly 24 k may be considered to have a cross-axis singleenveloping gear system. The adjustment assembly 24 k may be configuredto be a high speed system.

With reference to FIGS. 19A-19D, an adjustment assembly 24 m accordingto the principles of the present disclosure is provided. The structureand function of the adjustment assembly 24 m may be substantiallysimilar to that of the adjustment assembly 24 (FIGS. 1-3), apart fromany exceptions described below and/or otherwise shown in the figures.Accordingly, the structure and/or function of similar features will notbe described again in detail. In addition, like reference numerals areused hereinafter and in the drawings to identify like features, whilelike reference numerals containing letter extensions (i.e., “m”) areused to identify those features that have been modified.

The adjustment assembly 24 m includes a spindle screw or lead screw 56 jhaving outer threads 66 j and an adjustment subassembly 58 m. Theadjustment subassembly 58 m includes a first gear or cylindrical worm 80j having helical outer threads 82 j, a second gear or enveloping worm 86m having external teeth 84 m and internal thread 90 m, a pair of bearingbushings 78, a pair of washers 1600, and a gearbox assembly 1200. Thegearbox assembly 1200 includes a gearbox 400 a and a plurality offasteners 1202. The gearbox 400 a includes first and second portions 402a, 404 a. The adjustment assembly 24 m may alternatively include any ofthe other gearbox assemblies described here. While not shown, theadjustment subassembly 58 m may further include a support frame (e.g.,support frame 74 of FIGS. 1-3) a pair of cover shells (e.g., first andsecond cover shells 116, 118 of FIGS. 1-3).

The threads 66 j of the spindle screw 56 j may be trapezoidal anddefined by Tr 8×3 (P1.5) (8 mm nominal diameter, 3 mm lead, and 1.5 mmpitch). The adjustment assembly 24 j may have a minimum axial strengthof 19 kN and be considered a normal-strength adjustment assembly. Thesecond gear 86 m may be an enveloping worm gear. Therefore, theadjustment assembly 24 k may be considered to have an envelopingorthogonal gear system. The adjustment assembly 24 m may be configuredto be a ultra-high speed system.

In accordance with the principles of the present disclosure, a powerlength adjustment assembly may include a gearbox assembly, a gearsystem, and a spindle screw. The gearbox assembly may include a gearboxand a plurality of fasteners. The gearbox may be an open-type gearbox ora close-type gearbox. The gearbox may include two parts or portionshaving mating surfaces with three-dimensional curvature, such asellipsoidal, conical, or spherical. The fasteners may include screws(e.g., self-tapping screws), rivets (e.g., discrete rivets, integralrivets), bolts, or any combination thereof. The gear system may be anenveloping orthogonal gear system or a helical orthogonal gear system.The gear system may be configured to be a comfort speed system, a highspeed system, or a ultra-high speed system. The spindle screw may be anormal-strength lead screw or an enhanced-strength lead screw.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A gearbox for a vehicle seat adjustment mechanismcomprising: a first portion including a first body, the first bodydefining a first longitudinal recess and a first peripheral recess influid communication with the first longitudinal recess, and including afirst curved surface, the first curved surface being concave; and asecond portion including a second body, the second body define a secondlongitudinal recess and a second peripheral recess in fluidcommunication with the second longitudinal recess, and including asecond curved surface, the second curved surface being convex and havingan equal and opposite curvature compared to the first curved surface,wherein in an assembled configuration: the first curved surface is incontact with the second curved surface, the first longitudinal recesscommunicates with the second longitudinal recess to define alongitudinal passage, and the first peripheral recess communicates withthe second peripheral recess to define a peripheral receptacle.
 2. Thegearbox of claim 1, wherein the first curved surface and the secondcurved surface both define (i) a portion of an ellipsoidal surface, (ii)a portion of a conical surface, or (iii) a portion of a sphericalsurface.
 3. The gearbox of claim 1, wherein the first curved surface andthe second curved surface both define a portion of an ellipsoidalsurface, the ellipsoidal surface having a first radius in a range of 190mm to 200 mm and a second radius in a range of 240 to 250 mm.
 4. Thegearbox of claim 1, wherein the first curved surface and the secondcurved surface both define a portion of a conical surface, the conicalsurface defining an average opening angle in a range of 165° to 172°. 5.The gearbox of claim 1, wherein the first curved surface and the secondcurved surface both define a portion of a spherical surface, thespherical surface having a radius in a range of 190 mm to 200 mm.
 6. Thegearbox of claim 1, wherein: one of the first portion and the secondportion includes a frusto-conical projection extending from a respectiveone of the first curved surface and the second curved surface, the otherof the first portion and the second portion includes a frusto-conicalreceptacle defined by a respective one of the first curved surface andthe second curved surface, and in the assembled configuration, thefrusto-conical receptacle receives the frusto-conical projection.
 7. Thegearbox of claim 6, wherein: the one of the first portion and the secondportion further includes an annular projection extending from therespective one of the first curved surface and the second curvedsurface, the annular projection being disposed around a base of thefrusto-conical projection and coaxial with the frusto-conicalprojection, the other of the first portion and the second portionfurther includes an annular depression defined by a respective one ofthe first curved surface and the second curved surface, the annulardepression coaxial with the frusto-conical receptacle, and in theassembled configuration, the annular depression receives the annularprojection.
 8. The gearbox of claim 7, wherein the frusto-conicalprojection includes a first frusto-conical projection and a secondfrusto-conical projection, the frusto-conical receptacle includes afirst frusto-conical receptacle and a second frusto-conical receptacle,the annular projection includes a first annular projection and a secondannular projection, and the annular depression includes a first annulardepression and a second annular depression.
 9. The gearbox of claim 1,further comprising: an elastic layer disposed on at least one of thefirst curved surface or the second curved surface.
 10. The gearbox ofclaim 1, wherein: one of the first portion and the second portionincludes an integral rivet extending from a respective one of the firstcurved surface and the second curved surface, and the other one of thefirst portion and the second portion includes an aperture defined in arespective one of the first curved surface and the second curvedsurface, the aperture being configured to receive a portion of theintegral rivet.
 11. The gearbox of claim 1, further comprising: aplurality of fasteners configured to couple the first portion and thesecond portion to each other.
 12. The gearbox of claim 1, wherein: thegearbox is configured to house at least a portion of a cross-axis gearsystem and a spindle screw, and the cross-axis gear system includes afirst gear in operative communication with a second gear, the secondgear being in operative communication with the spindle screw.
 13. Thegearbox of claim 12, wherein the gear system is configured to operate atone of: (i) a comfort speed having a linear adjusting speed ranging from17 mm/s to 22 mm/s, (ii) a high speed having a linear adjusting speedranging from 50 mm/s to 55 mm/s, or (iii) a ultra-high speed having alinear adjusting speed ranging from 80 mm/s to 85 mm/s.
 14. The gearboxof claim 12, wherein the first gear is a cylindrical worm gear and thesecond gear is one of a helical gear or a single enveloping worm gear.15. A vehicle seat adjustment assembly comprising: a gearbox assemblyincluding, a first portion including a first body, the first bodydefining a first longitudinal recess and a first peripheral recess influid communication with the first longitudinal recess, and including afirst curved surface, the first curved surface being concave, and asecond portion including a second body, the second body defining asecond longitudinal recess and a second peripheral recess, and includinga second curved surface, the second longitudinal recess cooperating withthe first longitudinal recess to define a longitudinal passage, thesecond peripheral recess cooperating with the first peripheral recess todefine a peripheral receptacle, the second curved surface being convex,having an equal and opposite curvature compared to the first curvedsurface, and being in contact with the first curved surface; a gearsystem including, a first gear disposed at least partially within theperipheral receptacle, the first gear including a first external thread,the first gear configured to rotate about a first axis, and a secondgear disposed at least partially within the longitudinal passage, thesecond gear including external teeth and an internal thread and defininga gear passage, the external teeth in operative communication with thefirst external thread, the second gear configured to rotate about asecond axis perpendicular to the first axis; and a spindle screwextending through the gear passage and including a second externalthread, the second external thread in operative communication with theinternal thread.
 16. The vehicle seat adjuster assembly of claim 15,wherein the first curved surface and the second curved surface bothdefine (i) a portion of an ellipsoidal surface, (ii) a portion of aconical surface, or (iii) a portion of a spherical surface.
 17. Thevehicle seat adjustment assembly of claim 15, wherein the second gear isone of (i) a helical gear or (ii) a single enveloping worm gear.
 18. Thevehicle seat adjustment assembly of claim 15, wherein: the secondexternal thread is a trapezoidal thread, and the spindle screw has a 3mm lead, a 1.5 mm pitch, and one of a (i) 8 mm nominal diameter and (ii)a 9 mm nominal diameter.
 19. The vehicle seat adjustment assembly ofclaim 15, wherein the gear system is configured to operate at one of:(i) a comfort speed having a linear adjusting speed ranging from 17 mm/sto 22 mm/s, (ii) a high speed having a linear adjusting speed rangingfrom 50 mm/s to 55 mm/s, or (iii) a ultra-high speed having a linearadjusting speed ranging from 80 mm/s to 85 mm/s.
 20. The gearboxassembly of claim 15, wherein: one of the first portion and the secondportion includes a frusto-conical projection and an annular projectionextending from a respective one of the first curved surface and thesecond curved surface, the annular projection being disposed around abase of the frusto-conical projection and coaxial with thefrusto-conical projection, other of the first portion and the secondportion includes a frusto-conical receptacle and an annular depressiondefined by a respective one of the first curved surface and the secondcurved surface, the annular depression coaxial with the frusto-conicalreceptacle, and the frusto-conical receptacle is configured to receivethe frusto-conical projection and the annular depression is configuredto receive the annular projection.